Vehicles, for example passenger motor vehicles or trucks, can use what is known as a hybrid drive for driving the vehicle. The hybrid drive can comprise, for example, an internal combustion engine, such as a petrol engine or diesel engine, and an electric motor. In vehicles having a hybrid drive, what are known as hybrid vehicles, the running time of the internal combustion engine is limited. In the phases, in which the internal combustion engine is running, the load point of the internal combustion engine is as a rule comparatively high, with the result that there is only a small pressure gradient between the surroundings and the intake manifold. A pressure gradient of this type is usually used in internal combustion engines, however, to flush a filter device, for example an activated carbon container, which stores fuel gases from a tank which is assigned to the internal combustion engine. As a consequence, additional running times of the internal combustion engine are necessary, in order to achieve the necessary flushing rates for the filter. This can increase the fuel consumption or the emissions of the vehicle.
In this context, DE 10 2007 002 188 A1 discloses a hybrid vehicle having an internal combustion engine and an electric motor. The hybrid vehicle has a tank ventilating system which comprises at least one fuel tank and a suction line which leads from a filter device which can be regenerated to an intake section of the internal combustion engine. Moreover, a control apparatus is provided which can actuate various valve devices in order to flush the filter device, with the result that ambient air can be fed to the internal combustion engine through the filter device and the suction line. The control device is additionally configured in such a way that, in the case of pure electric operation of the hybrid vehicle, it switches on the internal combustion engine depending on a loading state of the filter device or a flushing gas concentration.
DE 102 00 016 B4 relates to a method and system for flushing a container for a vehicle with a hybrid drive. The hybrid drive comprises an internal combustion engine and an electric motor. As soon as it is determined that a flushing operation is required, the engine is switched on if it is not already switched on and is instructed to operate at low positions of the throttle valve, with the result that there is more vacuum in the intake manifold, in order to suck in the fuel vapor.